It is generally known to apply automation in the following areas of business:                home-automation,        industry,        solar panels systems, and        smart-grids.        
An essential need of home-automation systems is the ability to provide a reliable system installable in every new and retrofitted house with power-line communication between each module.
Industry needs are related to the control of appliances, electrical consumption of appliances by monitoring the energy usage of the electrical appliances and avoiding of power-peaks by dispatching the load along the time.
An essential need of solar panel systems is the ability to provide a reliable communication system between the inverters. Today the industry trend is to develop micro-inverters, in the sense that each solar panel will contain its own micro-inverter. The inverters of each solar panel needs to communicate with the inverters of other solar panels.
It is know from prior art, for example from the Swiss company DigitalStrom to use power-line communication by generating voltage spikes in the switch panel and reading a current spike generated by a module close to the load. The system used by digitalStrom is described in International publication WO2011/094873 A1.
The company Insteon patented a concept of powerline and RF network in U.S. Pat. No. 7,345,998 B2. Insteon patented the concept of network of the so called “Insteon plugs” that communicate on the powerline during the zero-crossing period and use RF radio signal to couple the communication between different phases.
An other powerline communication technology is the X10 that communicates only during the zero crossing phase. It is based on messages generated by an emitter destined to a specific receiver.
Patent publication U.S. 2003/0040813 A1 speaks about distributed control of a home automation system. In this patent publication each device contains a microcontroller and a load control, and the main use of the device described in the patent publication is for lightning control. The patent publication describes the capability to store scenes in the microcontroller and be able to reproduce them with a simple trigger message. The patent publication fails to describe any power line communication and there is no mention that the system fits behind existing plugs.
Patent publication U.S. 2002/169846 describes a method to select a head cluster among nodes. The method described is based on a weighted factor: the more points the node gets, the higher is the chance to be selected as head.
Patent application EP 1978689 A1 describes a mechanism based on token weight to elect a head node. The approach is also based on a weighted mechanism, as in one of the previously mentioned patent publications with the difference that in this approach less bandwidth is needed as low-weight token are not propagated. In this approach, only one head cluster is elected, no hierarchy is present and no voting mechanism is described.